The present invention relates to an apparatus for reconnoitering terrain from an aircraft and more particularly to a system utilizing a television camera for such reconnoitering.
A disadvantage of televised aerial reconnaissance is that the strip of ground that can be covered by a television camera is very narrow. This results from the narrow resolving power of video cameras. In British Pat. No. 1,358,036 an apparatus is disclosed whereby the width of the strip of ground that can be reconnoitered by a television camera is broadened by linearly arranging a number of individual images into an image line. Individual images are obtained by tilting a mirror about the optic axis of the television camera or televising the images. While this system does broaden the scanned strip, it produces several problems.
The most significant problem is that a different scale results for each of the individual images of the line since the angle of incidence i.e., the angle of the viewing direction with respect to the horizontal, changes from image to image. Another problem with the prior art system is that the distortion of individual images differs along the image line so that later evaluation of the total images poses difficulties.
In view of the above, the principal object of the present invention is to provide an apparatus for reconnoitering terrain from the air wherein the scale of size of all the individual images and the distortion within each individual image remains constant.